1. Field of the Invention
The present invention relates to a semiconductor memory device, and more particularly, to a signal line driving circuit and a semiconductor memory device employing the same.
2. Description of the Related Art
The speed and integration of semiconductor memory devices have been steadily increasing over the past few years. With the increasing use of battery operated systems such as notebook computers, the need for semiconductor memory devices which consume minimal power has also increased. Usually, the semiconductor memory device includes an internal power supply voltage generator for low voltage operation and low power consumption. The internal power supply voltage generator receives an externally supplied power supply and generates an internal power supply having a voltage level that is lower than the voltage level of the externally supplied power supply. Accordingly, the internal power supply voltage is used to operate the main circuit of the semiconductor memory device thereby reducing power consumption. However, in a high speed multi-bit semiconductor memory device having a multiplicity of data input/output pins, the power consumption of the internal power supply voltage generator greatly increases. In the semiconductor memory device, power is mainly consumed in the write path and in the read path. The write path includes the data input buffer, the data input/output line write driver, the data input/output line, the input/output line write driver, the input/output line, the column select line, and the bitline. The read path includes the bitline, the column select line, the input/output line, the data input/output line read driver, the data input/output line, and the data output buffer. A substantial amount of power is consumed by the data input/output line write driver, the input/output line write driver and the data input/output line read driver which drive signal lines which are long and have a high load.
The multi-bit semiconductor memory device having a multiplicity of data input/output pins, and thus a plurality of data input/output lines and input/output lines which are simultaneously driven during write or read operation, has an increased number of data input/output line write drivers, input/output line write drivers, and data input/output line read drivers which leads to increased power consumption. Also, in a high speed multi-bit synchronous DRAM, the external power supply voltage is used to power the drivers in order to increase the operating speed of the device. Doing so, however, increases power consumption.